Saturday, August 3, 2013

Star absolute magnitude

We just learned that when scientists want to measure how hot a star is,
they use something called stellar classification.

Another thing they measure for stars is how bright they are.
They call this absolute magnitude.

We can't just measure how bright stars look to us in our sky,
because some are close (like our sun) and some are very very far away.

So we measure how bright a star would be if we were looking at it from 32.6 light years away.

They go from -15 which is very very bright, to 20 which is not very bright at all.
Our sun has an absolute magnitude of 5, so it's about in the middle of the brightness levels.
(from: wikipedia - stellar classification)